Small children occasionally entangle themselves within the cords of window coverings, such as venetian blinds, when guardians fail to properly supervise the children. A child can become entangled within the cords of a venetian blind by pulling on a lift cord extending between the bottom rail and the headrail. Such pulling raises the bottom rail and creates an inner cord loop that can become entangled with the child. This can occur because the bottom rail of the venetian blind is not prevented from moving upward. In some cases, such entanglement causes injury or even the death of the child. Consequently, many consumers prefer to purchase window coverings that help mitigate, if not eliminate, the risk of such cord entanglement.
U.S. Pat. Nos. 4,909,298, 5,630,458, 6,484,787 and 6,637,493 disclose safety mechanisms that generally attempt to prevent injury to children from entanglement with operator cords that extend from the headrail to raise and lower the blind. These disclosed safety mechanisms generally attempt to position the pull cords of window coverings that are used to lift or lower blinds away from a small child's reach to prevent the child from becoming entangled within the operator cords. Such devices, however, often fail to prevent the entanglement of children with an inner lift cord of a lowered window covering because they do not prevent the bottom rail of such window coverings from being raised. Consequently, children can pull the inner lift cords away from the window covering and become entangled within the cords that are pulled away from the window covering.
U.S. Pat. Nos. 7,000,672 and 6,918,425 disclose methods of affixing the lift cords of a window covering to prevent the lift cords or any operator cords from being pulled by a child. The disclosed methods usually require the lift cords of the window covering to be affixed to the window frame to prevent repositioning or substantial movement of the bottom rail of the window covering by an operator cord or by wind or other force acting through an open window.
For example, U.S. Pat. No. 7,000,672 teaches that guide cords should extend through the bottom rail of the window covering and be affixed to the bottom of a window frame. A cord lock mechanism in the bottom rail of the window covering may then be disengaged to reposition the blind along the affixed guide cords by tilting the bottom rail to move the cord lock to an unlocked position. Once the cord lock within the bottom rail is moved to the unlocked position, the bottom rail may be raised or lowered along the affixed guide cords.
U.S. Pat. Nos. 7,117,918 and 5,533,559 also disclose mounting devices for the guide cords of a blind that are affixed to a window frame. U.S. Pat. No. 7,117,918 to Franssen, for example, discloses a two part mounting device that includes a ratchet and pawl mechanism. One portion of the mounting device is affixed to the window frame and the other portion is slidable along the affixed portion to permit the distance between the affixed guide cords to be altered. The sliding portion can also be slide completely off the affixed portion to disconnect the guide cords from the window frame.
Additionally, U.S. Pat. No. 6,948,546 discloses a device for affixing the bottom rail of a window covering to a window frame by connecting the bottom rail to the window frame by releasable retaining cords that extend from the headrail of a venetian blind. The retaining cords extend from the headrail of the window covering and are releasably connected to the window frame by a sheltering cap that is connected to a snap member affixed to the window frame. When a child's neck or head engages the retaining cords, the cap disconnects from the snap member, permitting the retaining cords to hang from the bottom rail.
Such loose retaining cords, however, expose children to entanglement dangers associated with such cords. Further, the cap and snap members are disclosed for use with non-cord operated blinds. Such devices are not designed for use with cord operated blinds, such as typical venetian blinds or cellular shades because those window coverings do not have guide cords or retaining cords affixed to the window frame adjacent the shade or blind. Instead, such blinds typically have lift cords that extend from the headrail of a window covering to window covering material that are manipulated to raise or lower the window covering material.
U.S. Pat. Nos. 4,727,921 and 5,069,264 also disclose mechanisms for holding down the bottom rail of a window covering. Because the bottom rail of the window covering is held down, the blind can be prevented from swinging due to wind blowing through an open window. U.S. Pat. No. 5,069,264 discloses a hold down bracket that has a portion that is configured to attach to an end of a bottom rail and a portion that is configured with holes so it can be affixed to the window frame adjacent the window covering by screws or nails. Such hold down brackets maintain the position of the window covering. The bottom rail of the window covering can be released from the bracket to raise or reposition the window covering.
U.S. Pat. No. 4,727,921 discloses a window covering that has spring biased projections that extend from the ends of a bottom rail to engage sides of a window frame adjacent the window covering. The projections may interlock within holes formed in the window frame, which can prevent the bottom rail from movement. The projections must be disengaged from the holes in order to raise the window covering.
Hold down devices such as the devices disclosed in U.S. Pat. Nos. 4,727,921 and 5,069,264 often limit a user to only one lowered position in which the bottom rail of a window covering may be affixed to the window frame. Further, hold down brackets such as the ones disclosed in U.S. Pat. No. 5,069,264 are often noticeable and can detract from the aesthetic effect of the window covering or the window frame.
A safety device is needed that prevents small children from pulling the inner lift cords of a window covering away from the blind to prevent the child from becoming entangled within the pulled portion of the inner lift cords. The safety device preferably prevents the bottom rail of a window covering from being substantially raised to prevent the pulling of such cords, but is adjustable to permit a user to adjustably lock the position of the bottom rail so the window covering can be maintained at one of several selected lowered positions.